Multi-actor damping systems and methods

ABSTRACT

A damping actor selector may be configured to transition a multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The multi-actor damping system may be used in a shock strut assembly to alter a damping curve of the shuck strut assembly. The damping actor selector may be coupled to a metering pin of a shock strut assembly. The damping actor selector may be configured to rotate the metering pin to transition the multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The first damping actor configuration may correspond to a first damping curve. The second damping actor configuration may correspond to a second damping curve. The first damping curve being different than the second damping curve.

FIELD

The present disclosure relates generally to a multi-actor damping systemand, more particularly, to a multi actor damping system for use in alanding gear system.

BACKGROUND

Shock absorbing devices are used in a wide variety of vehicle suspensionsystems for controlling motion of the vehicle and its tires with respectto the ground and for reducing transmission of transient forces from theground to the vehicle. Shock absorbing struts are a common component inmost aircraft landing gear assemblies. Shock struts control motion ofthe landing gear, and absorb and damp loads imposed on the gear duringlanding, taxiing, braking, and takeoff.

A shock strut generally accomplishes these functions by compressing afluid within a sealed chamber formed by hollow telescoping cylinders.The fluid generally includes both a gas and a liquid, such as hydraulicfluid or oil. One type of shock strut generally utilizes an“air-over-oil” arrangement wherein a trapped volume of gas is compressedas the shock strut is axially compressed, and a volume of oil is meteredthrough an orifice. The gas acts as an energy storage device, similar toa spring, so that upon termination of a compressing force the shockstrut returns to its original length. Shock struts also dissipate energyby passing the oil through the orifice so that as the shock absorber iscompressed or extended, its rate of motion is limited by the dampingaction from the interaction of the orifice and the oil.

SUMMARY

A method for changing a damping curve of a shock strut assembly isdisclosed herein. The method may comprise: rotating, via a damping actorselector, a metering pin from a default position about a centerline ofthe metering pin in a first direction, the default positioncorresponding to a first damping actor configuration; setting, via thedamping actor selector, a first actor angle corresponding to a seconddamping actor configuration.

In various embodiments, the first damping actor configuration mayinclude a first damping curve, the second damping actor configurationmay include a second damping curve, and the first damping curve and thesecond damping curve may be different. The first damping curve may befor conventional landing of an aircraft. The second damping curve may befor a catapult launch of the aircraft. The method may further compriserotating, via the damping actor selector, the metering pin from thefirst actor angle to a second actor angle. The second actor angle maycorrespond to the first damping actor configuration. The second actorangle may correspond to a third damping configuration. The first dampingactor configuration may include a first damping curve, the seconddamping actor configuration may include a second damping curve, thethird damping configuration may include a third damping curve, whereinthe first damping curve is different from the second damping curve,wherein the second damping curve is different than the first dampingcurve, and wherein the first damping curve is different from the thirddamping curve. The first actor angle may be a relative clock anglebetween the metering pin and a strut cylinder.

A method of selecting a damping configuration of a shock strut assemblyfor an aircraft is disclosed herein. The method may comprise: sending,by a controller, a catapult launch command to a launch bar lock and adamping actor selector; extending, by the controller, the launch barlock to a deck of the aircraft to configure the aircraft for a catapultlaunch; and transitioning, via the controller, the damping actorselector from a first damping actor configuration to a second dampingactor configuration in response to the catapult launch command.

In various embodiments, the first damping actor configuration maycorrespond to a first damping curve, the second damping actorconfiguration may correspond to a second damping actor curve, and thefirst damping curve and the second damping actor curve may be different.The method may further comprise transitioning the damping actor selectorfrom the first damping actor configuration to the second damping actorconfiguration further comprises setting an actor angle, wherein theactor angle is a relative clock angle between a metering pin and a strutcylinder. The method may further comprise transitioning, via thecontroller, the damping actor selector from the second damping actorconfiguration to the first damping actor configuration in response toreceiving a signal from a sensor that a wheel is not experiencing aload. The method may further comprise sending, by the controller, are-engage command to the launch bar lock and the damping actor selector;and transitioning, via the controller, the damping actor selector fromthe second damping actor configuration to the first damping actorconfiguration in response to the re-engage command.

A shock strut assembly is disclosed herein. The shock strut assembly maycomprise: a strut cylinder including a primary chamber; a strut piston,the strut cylinder configured to receive the strut piston; an orificesupport tube positioned within the primary chamber of the strutcylinder; a main orifice assembly disposed within the orifice supporttube, the main orifice assembly including a main orifice plate; ametering pin positioned within the primary chamber, the metering pindefining an axis; and a damping actor selector operably coupled to themain orifice plate, the damping actor selector configured to rotate themain orifice plate and transition the shock strut assembly from a firstdamping actor configuration to a second damping actor configuration.

In various embodiments, the damping actor selector may comprise ahydraulic actuation or pneumatic actuation. The damping actor selectormay comprise at least one of an electric stepper or a servo motor. Thedamping actor selector may comprise a piston head coupled to themetering pin. The metering pin may rotate in response to the piston headtraveling linearly along the axis. The first damping actor configurationmay include a first damping curve, the second damping actorconfiguration may include a second damping curve, and the first dampingcurve may be different than the second damping curve.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1 illustrates a shock strut assembly, in accordance with variousembodiments;

FIG. 2 illustrates a detail of a shock strut assembly, in accordancewith various embodiments;

FIG. 3 illustrates a portion of a shock strut assembly, in accordancewith various embodiments;

FIG. 4 illustrates a portion of a shock strut assembly including flowrestrictors in a retracted position;

FIG. 5 illustrates a portion of a shock strut assembly including flowrestrictors in a deployed position;

FIG. 6 illustrates a flow restrictor, in accordance with variousembodiments;

FIG. 7 illustrates an orbit cam, in accordance with various embodiments;

FIG. 8A illustrates a perspective and side view of a metering pin, inaccordance with various embodiments;

FIG. 8B illustrates a cross-section of a metering pin of FIG. 8A, inaccordance with various embodiments;

FIG. 9A illustrates a portion of a shock strut assembly in a bypassclosed position, in accordance with various embodiments;

FIG. 9B illustrates a portion of a shock strut assembly in a bypass openposition, in accordance with various embodiments;

FIG. 10A illustrates a cross-section of a portion of a shock strutassembly having a first damping actor configuration, in accordance withvarious embodiments;

FIG. 10B illustrates a cross-section of a portion of a shock strutassembly having a first damping actor configuration, in accordance withvarious embodiments;

FIG. 11A illustrates a cross-section of a portion of a shock strutassembly having a first orientation, in accordance with variousembodiments;

FIG. 11B illustrates a cross-section of a portion of a shock strutassembly having a first orientation, in accordance with variousembodiments;

FIG. 12A illustrates a cross-section of a portion of a shock strutassembly having a second orientation, in accordance with variousembodiments;

FIG. 12B illustrates a cross-section of a portion of a shock strutassembly having a second orientation, in accordance with variousembodiments;

FIG. 13A illustrates a cross-section of a portion of a shock strutassembly having a third orientation, in accordance with variousembodiments;

FIG. 13B illustrates a cross-section of a portion of a shock strutassembly having a third orientation, in accordance with variousembodiments;

FIG. 14A illustrates a cross-section of a portion of a shock strutassembly having a second damping actor configuration, in accordance withvarious embodiments;

FIG. 14B illustrates a cross-section of a portion of a shock strutassembly having a second damping actor configuration, in accordance withvarious embodiments;

FIG. 15 illustrates a portion of a main orifice assembly with a mainorifice plate, metering pin, and flow restrictors hidden, in accordancewith various embodiments;

FIG. 16 illustrates an exploded view of a main orifice assembly, inaccordance with various embodiments;

FIG. 17A illustrates a portion of a shock strut assembly during strutcompression, in accordance with various embodiments;

FIG. 17B illustrates a portion of a shock strut assembly during strutextension, in accordance with various embodiments;

FIG. 18 illustrates a portion of a shock strut assembly, in accordancewith various embodiments;

FIG. 19 illustrates a metering plate assembly and a metering pin, inaccordance with various embodiments;

FIG. 20 illustrates a portion of a shock strut assembly, in accordancewith various embodiments;

FIG. 21 illustrates a portion of a shock strut assembly, in accordancewith various embodiments;

FIG. 22 illustrates an aircraft control system, in accordance withvarious embodiments; and

FIG. 23 illustrates a method of using a damping actor selector, inaccordance with various embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical changes and adaptations in design andconstruction may be made in accordance with this disclosure and theteachings herein without departing from the spirit and scope of thedisclosure. Thus, the detailed description herein is presented forpurposes of illustration only and not of limitation.

A multi-actor damping system is disclosed. The multi-actor dampingsystem may be used in a shock strut assembly to alter a damping curve ofthe shuck strut assembly. A “damping curve,” as disclosed herein is therelationship between shock strut damping and stroke. A multi-actordamping system, as disclosed herein, may be configured to alter adamping curve by clocking a metering pin and/or main orifice plate tovarious positions. In various embodiments, a metering pin of a shockstrut assembly may comprise a damping profile. A “damping profile,” asdisclosed herein, is a varying cross sectional area of the metering pinover its length to establish a respective damping curve associated withthe metering pin.

In various embodiments, a shock strut assembly may include a pluralityof damping actor configurations. A “damping actor configuration,” asdisclosed herein, is any configuration of the shuck strut assembly thatproduces a unique damping curve. A main orifice assembly of the shockstrut assembly may be configured to produce any number of damping actorconfigurations. The main orifice assembly may be configured to add orsubtract flow are from the damping profile in response to altering aposition of the main orifice assembly and/or the metering pin. The shuckstrut assembly may include various actor angles corresponding to arespective damping actor configuration. An “actor angle,” as disclosedherein, is a relative clock angle between the metering pin and a strutcylinder. The actor angle determines which damping actor configurationis active.

The multi-actor damping system uses the actor angle to add or subtractflow area from the damping profile of the metering pin and/or alter adischarge coefficient. The system may allow selection of variouspre-defined damping actor configurations. The strut performance may beenhanced by allowing selection of a damping profile based on a givenactivity of an aircraft (e.g., a landing damping actor, a catapultdamping actor, a taxi damping actor, a short takeoff and verticallanding (STOVL) damping actor, a percolation damping actor, or the like.

Referring now to FIG. 1, a shock strut assembly 100 for use in a landinggear system, in accordance with various embodiments, is illustrated. Theshock strut assembly 100 may comprise a strut cylinder 110, a strutpiston 120, a metering pin 140, an orifice support tube 150, and a mainorifice assembly 160. Strut piston 120 may be operatively coupled tostrut cylinder 110 as described herein. Strut cylinder 110 may beconfigured to receive strut piston 120 in a manner that allows the twocomponents to telescope together and absorb and/or dampen forcestransmitted thereto. In various embodiments, a liquid, such as ahydraulic fluid and/or oil may be located within strut cylinder 110. Agas, such as nitrogen or air, may also be located within strut cylinder110. Strut cylinder 110 and strut piston 120 may, for example, beconfigured to seal such that fluid contained within strut cylinder 110is prevented from leaking as strut piston 120 translates relative tostrut cylinder 110.

Shock strut assembly 100 may comprise a low pressure, primary chamber130 in which oil and gas can mix. In this regard, a volume of gas (alsoreferred to herein as a primary chamber gas volume) 131 and a volume ofoil (also referred to herein as an oil volume) 133 may be containedwithin primary chamber 130. A portion of primary chamber 130 may containthe primary chamber gas volume 131 and may be referred to as a primarygas chamber 132. Similarly, the portion of primary chamber 130containing the oil volume 133 may be referred to herein as an oilchamber 134. Dashed line 135 represents the level of oil volume 133, orthe interface between the oil chamber 134 and the primary gas chamber132. Stated differently, the oil volume 133 may be located below dashedline 135 and primary chamber gas volume 131 may be located above dashedline 135. In this regard, the interface between the oil chamber 134 andthe primary gas chamber 132 may move relative to primary chamber 130depending on the position of strut piston 120 relative to strut cylinder110.

The metering pin 140 and the orifice support tube 150 may be positionedwithin primary chamber 130. The metering pin 140 may translate withstrut piston 120 with respect to main orifice assembly 160. In variousembodiments, the metering pin 140 may be configured to rotate about acenterline of the metering pin 140. In various embodiments, the orificesupport tube 150 may be configured to rotate about a centerline of theorifice support tube 150. By rotating the metering pin 140 or theorifice support tube 150, the shock strut assembly 100 may change from afirst damping actor configuration to a second damping actorconfiguration.

In various embodiments, the shock strut assembly 100 further comprises adamping actor selector 170. The damping actor selector 170 is configuredto rotate metering pin 140 relative to the strut piston 120. In variousembodiments, the damping actor selector 170 may be coupled to theorifice support tube 150 and configured to rotate the orifice supporttube 150 relative to the metering pin 140. The damping actor selector170 may provide position control by direct drive, transmitted through alinkage, or any other method of position control known in the art. Forexample, the damping actor selector 170 may comprise hydraulic orpneumatic actuation. In this regard, pressure may be used to drive apiston head of the damping actor selector 170 linearly along thecenterline of metering pin 140. As the piston moves, it may cause themetering pin 140 to rotate due to a screw thread interface between themetering pin 140 and the piston of the damping actor selector 170.

In various embodiments, external supply pressure may be applied by oilvolume 133 in oil chamber 134 and automatically return the damping actorselector to a neutral or default damping actor configuration. Thepressure may be configured to translate the piston of the damping actorselector along the centerline of the metering pin 140 to change dampingactor configurations. This configuration may provide an inherent safetyfeature of providing its own power source to return the damping actorselector 170 to a default damping actor configuration.

In various embodiments, the damping actor selector 170 may comprise anelectric stepper, servo motor, or the like. A stepper motor may provideaccurate angular positioning with an open loop design. A servo motor mayproduce accurate position and/or may provide a closed loop system. Thedamping actor selector 170 may interface with an aircraft controlsystem. The aircraft control system may be configured to control dampingactor selector 170 and/or alter the shock strut assembly from a firstdamping actor configuration to as second damping actor configuration.

Referring now to FIG. 2, detail A of shock strut assembly 100 from FIG.1, in accordance with various embodiments, is illustrated. In variousembodiments, main orifice assembly 160 further comprises a main orificeplate 180. Main orifice plate 180 may be disposed in a recess of orificesupport tube 150. Main orifice plate is coupled to first flow restrictor162 and/or second flow restrictor 164. The first flow restrictor 162 andthe second flow restrictor 164 may each comprise an aperture 165extending through the flow restrictor and defining a fulcrum about whichfirst flow restrictor 162 and second flow restrictor 164 pivot. Mainorifice plate 180 may be configured to rotate with the metering pin 140.For example, when metering pin 140 is rotated, it transitions torque tothe main orifice plate 180 via interface 195 between an aperture in mainorifice plate 180 and a side of metering pin 140. In variousembodiments, main orifice plate 180 may be configured to rotate withorifice support tube 150 relative to metering pin 140.

In various embodiments, the main orifice assembly 160 further comprisesa first orbit cam 167 and a second orbit cam 169. First orbit cam 167and second orbit cam 169 may be configured to remain stationary asmetering pin 140 and main orifice plate 180 rotate. Each orbit cam isconfigured to guide a respective flow restrictor from a first dampingactor configuration to a second damping actor configuration. Forexample, as main orifice plate 180 rotates about the centerline ofmetering pin 140, a head portion of a respective flow restrictor isguided in a respective orbit cam. For example, head portion 610 of firstflow restrictor 162 may be guided in a respective track or groove ofsecond orbit cam 169. The track or groove of second orbit cam 169 may beconfigured to cause first flow restrictor 162 to pivot about the fulcrumeither towards the metering pin 140 or away from the metering pin 140.

Referring now to FIG. 3, an exploded view of a main orifice assembly160, in accordance with various embodiments, is illustrated. In variousembodiments, main orifice assembly 160 further comprises a main orificeplate mount 182 and a main orifice plate retainer 184. The main orificeplate mount 182 may be configured to allow the main orifice plate 180 tobe restrained axially and/or also allow the main orifice plate to rotatefreely about the centerline of metering pin 140. In various embodiments,the main orifice plate retainer 184 is configured to retain the mainorifice plate mount 182 axially. For example, main orifice plateretainer 184 may couple to the main orifice plate mount 182 and hold themain orifice plate mount 182 in place.

In various embodiments, the main orifice assembly 160 further comprisesa first spring 192 and a second spring 194. Each spring may be coupledto a respective flow restrictor. For example, first spring 192 iscoupled to first flow restrictor 162 and second spring 194 is coupled tosecond flow restrictor 164. Each spring may be configured to load arespective flow restrictor against metering pin 140 in a respectivedamping actor configuration. Each spring may comprise a torsion spring,or the like. For example, first spring 192 may be configured to apply atorque to first flow restrictor 162 about the fulcrum defined byaperture 165 of the first flow restrictor 162 in a first damping actorconfiguration. In doing so, a damping curve of the shock strut assembly100 may be altered.

In various embodiments, the main orifice plate 180 may further comprisea plate portion 185 and a plurality of lugs 186. The plurality of lugs186 may extend axially from a surface of plate portion 185. Each flowrestrictor may couple to a first lug and a second lug from the pluralityof lugs. For example, first flow restrictor 162 may be coupled to firstlug 187 and second lug 188 form the plurality of lugs 186.

Referring now to FIG. 4, a cross-section of main orifice assembly 160 ina first damping actor configuration, in accordance with variousembodiments, is illustrated. In the first damping actor configuration,first flow restrictor 162 and second flow restrictor 164 may be fullyretracted. “Fully retracted,” as disclosed herein, occurs when each flowrestrictor is not in contact with metering pin 140. While fullyretracted, the first flow restrictor 162 and the second flow restrictor164 have little to no effect on the damping curve. In variousembodiments, when the first flow restrictor 162 and the second flowrestrictor 164 are retracted, the damping curve is based on a dampingcurve associated with a profile of the metering pin 140.

Referring now to FIG. 5, a cross-section of main orifice assembly 160 ina second damping actor configuration, in accordance with variousembodiments, is illustrated. In the second damping actor configuration,first flow restrictor 162 and second flow restrictor 164 may be fullydeployed. “Fully deployed,” as disclosed herein, occurs when each flowrestrictor is in contact with metering pin 140. While fully deployed,the first flow restrictor 162 and the second flow restrictor 164 effectthe damping curve and/or provide enhanced damping relative to the firstdamping actor configuration. In various embodiments, when the first flowrestrictor 162 and the second flow restrictor 164 are deployed, thedamping curve is based on a damping curve associated with the profile ofthe metering pin 140 as well as a profile of the first flow restrictor162 and the second flow restrictor 164.

Referring now to FIG. 6, various views of a flow restrictor 600, inaccordance with various embodiments, is illustrated. First flowrestrictor 162 and second flow restrictor 164 may be in accordance withflow restrictor 600. The flow restrictor 600 comprises a head portion610 and a restrictor portion 620.

Head portion 610 comprises a first mating surface 612 and a secondmating surface 614. First mating surface 612 may be disposed oppositesecond mating surface 614. First mating surface 612 may be configured tomate to a lug in the plurality of lugs 186 of main orifice plate 180 (asshown in FIG. 3). Similarly, second mating surface 614 may be configuredto mate to a lug in the plurality of lugs 186 of main orifice plate 180.Head portion 610 may further comprise an aperture 615 extending throughhead portion 610 from first mating surface 612 to second mating surface614. In various embodiments, the aperture 615 may act as a fulcrum forthe flow restrictor 600. Head portion may further comprise a protrusion618 extending from an outer surface 616 of head portion 610. Theprotrusion 618 may be configured to rotate the flow restrictor 600. Forexample, protrusion 618 may contact a respective orbit cam (e.g., firstorbit cam 167 for first flow restrictor 162) and/or protrusion 618 maybe guided by a track on an inner surface of a respective orbit duringdeploying and/or retracting flow restrictor 600.

In various embodiments, restrictor portion 620 may comprise a spine 622extending from head portion 610 to a tail end 629 of the flow restrictor600. In various embodiments, the spine 622 may define an arc or thelike. The spine 622 may be disposed between a first convex surface 621and a second convex surface 623. The spine 622, the first convex surface621, and the second convex surface 623 may be configured to interfacewith a flute and/or groove disposed in metering pin 140 (from FIG. 2)when the flow restrictor 600 is in a deployed position. In variousembodiments, the spine 622, the first convex surface 621 and the secondconvex surface 623 may define an outer surface of restrictor portion620.

In various embodiments, restrictor portion 620 may comprise a concavesurface 625 disposed opposite the first convex surface 621 and thesecond convex surface 623. The concave surface 625 may include a firstrecess 626 disposed therein. The first recess 626 may be configured toreceive a spring. The first recess 626 may be disposed on a portion ofthe concave surface 625 and a portion of head portion 610.

In various embodiments, head portion 610 may further comprise a secondrecess 619. Second recess 619 and first recess 626 may partially definea channel. The channel may be configured to receive a spring, inaccordance with various embodiments.

Referring now to FIG. 7, an orbit cam 700, in accordance with variousembodiments, is illustrated. In various embodiments, orbit cam 700 issemi-annular. The orbit cam may comprise a first mating surface 702 anda second mating surface 704. First mating surface 702 may include a malefastener 703. Second mating surface 704 may include a female fastener705. In various embodiments, the first mating surface 702 and secondmating surface 704 may both contain male fasteners or the first matingsurface 702 and second mating surface 704 may both contain femalefasteners. By having a male fastener on one mating surface and a femalemating fastener on a second mating surface, a first orbit cam may becoupled to a second orbit cam and both the first orbit cam and thesecond orbit cam may have the same geometry. For example, first orbitcam 167 and second orbit cam 169 may both be in accordance with orbitcam 700.

Orbit cam 700 may further comprise a guide ramp 710 disposed on aradially inner surface 712 of orbit cam 700. Guide ramp 710 may extendradially inward from the radially inner surface 712 from a first axiallyend and extend axially and circumferentially about radially innersurface 712. With combined reference to FIGS. 6 and 7, guide ramp 710may be configured to guide the protrusion 618 of a head portion 610 of aflow restrictor 600. For example, guide ramp 710 may alter an axialposition of protrusion 618 and either retract or deploy flow restrictor600.

Orbit cam 700 may further comprise an anti-rotation feature 720. Theanti-rotation feature 720 may be disposed on a radially outer surface722 of the orbit cam 700. The anti-rotation feature 720 may be a flatrecess 724 disposed on the radially outer surface 722. The anti-rotationfeature 720 may be configured to interface with a correspondinganti-rotation feature on the main orifice plate mount 182 (as shown inFIG. 3).

In various embodiments, orbit cam 700 comprises a proximal end 732 and adistal end 734 disposed distal in an axial direction from the proximalend 732. Orbit cam 700 may comprise a groove 736 disposed proximatedistal end 734. The groove 736 may be configured to receive a tonguefrom a mating main orifice plate (e.g., main orifice plate 180). Assuch, the main orifice plate may rotate while the orbit cam 700 mayremain stationary.

Referring now to FIG. 8A, a metering pin 140, in accordance with variousembodiments. The metering pin 140 may comprise an elongated member 805extending from a first end 801 to a second end 809 and defining acentral axis. The elongated member 805 may include a quadrilateralcross-section. In various embodiments, the quadrilateral cross-sectionmay comprise a trapezoidal cross-section, a square cross-section, or thelike. In various embodiments, the first end 801 may comprise aquadrilateral cross section (e.g., a trapezoidal cross section, a squarecross section, or the like). A square cross-section may provide enhancestorque transfer properties. A trapezoidal cross-section may providemistake proofing during assembly of a main orifice assembly. In variousembodiments, with reference now to FIG. 8B, a cross-section alongsection line A-A of metering pin 140 is illustrated, in accordance withvarious embodiments.

With combined reference now to FIGS. 8A and 8B, on a first side 802 ofthe quadrilateral cross section of the metering pin 140, the meteringpin 140 may comprise a first flute profile 810. In various embodiments,first flute profile 810 may comprise a groove 812 disposed in the firstside 802 of the quadrilateral cross section. In various embodiments, thegroove may be a V-groove, a V-groove with a fillet, or the like. Thefirst flute profile 810 may extend a length L1 of the metering pin 140.The length L1 of the first flute profile 810 may correspond to a fullstroke length of a strut stroke for a shock strut assembly (e.g., shockstrut assembly 100 from FIG. 1). In various embodiments, L1 may bebetween 75% and 95% of a length of metering pin 140. In variousembodiments, the first flute profile 810 may be disposed on a third side806 of the quadrilateral cross section of the metering pin 140. Thethird side 806 may be opposite the first side 802. The third side 806may comprise a groove 832 in accordance with groove 812.

In various embodiments, on a second side 804 of the quadrilateral crosssection of the metering pin 140, the metering pin 140 may comprise asecond flute profile 820. The second side 804 may be adjacent to thefirst side 802 and the third side 806. In various embodiments, secondflute profile 820 may comprise a groove 822 disposed in the second side804 of the quadrilateral cross section. In various embodiments, thegroove may be a V-groove, a V-groove with a fillet, or the like. Thesecond flute profile 820 may extend a length L2 of the metering pin 140.The length L2 of the second flute profile 820 may correspond toapproximately a half stroke length of a strut stroke for a shock strutassembly (e.g., shock strut assembly 100 from FIG. 1). In variousembodiments, L2 may be between 35% and 65% of a length of metering pin140. In various embodiments, the second flute profile 820 may bedisposed on a fourth side 808 of the quadrilateral cross section of themetering pin 140. The fourth side 808 may be opposite the second side.The fourth side 808 may comprise a groove 842 in accordance with groove822. In various embodiments, grooves 812, 822, 832, 842 may all be thesame.

In various embodiments, first flute profile 810 may be configured to beeffective across a full stroke range. In various embodiments, secondflute profile 820 may be configured to be effective from a fullyextended stroke to approximately half of a stroke. The combination offirst flute profile 810 and second flute profile 820 used in combinationis greater damping as a function of stroke compared to utilizing onlyfirst flute profile 810 or only second flute profile 820.

In various embodiments, with combined reference to FIGS. 6 and 8A-8B,grooves 812, 822, 832, 842 may all be configured to interface with arestrictor portion 620 of flow restrictor 600 when a flow restrictor 600is in a fully deployed position in a main orifice assembly. For example,a fillet portion 814 of groove 812 may be configured to interface withthe spine 622 of restrictor portion 620 of flow restrictor 600.Similarly, first convex surface 621 may be configured to interface withfirst wall 815 of groove 812 and the second convex surface 623 of therestrictor portion 620 of flow restrictor 600 may be configured tointerface with second wall 816 of groove 812.

Referring now to FIGS. 9A and 9B, a portion of a shock strut assemblyalong a top view, in accordance with various embodiments, isillustrated. In various embodiments, the orifice support tube 150 mayfurther comprise a coupling end 152 disposed axially adjacent to themain orifice plate 180. Main orifice plate 180 may comprise an aperture910. Aperture 910 may correspond to a cross-sectional shape of meteringpin 940 (e.g., a quadrilateral shape, or the like). The metering pin 940may be disposed in aperture 910 and configured to transfer torque fromthe metering pin 940 to the main orifice plate 180 in order to clock amain orifice assembly (e.g., main orifice assembly 160 from FIG. 3), inaccordance with various embodiments. In various embodiments, themetering pin 940 may be in accordance with the metering pin 140 fromFIGS. 8A-8B.

In various embodiments, coupling end 152 may comprise a clearanceaperture 151. Clearance aperture 151 may be configured to receive themetering pin 140 therethrough. Disposed radially outward from theclearance aperture 151, the coupling end 152 may further comprise afirst bypass alignment aperture 153. In various embodiments, thecoupling end 152 further comprises a second bypass alignment aperture155 disposed approximately 180 degrees from the first bypass alignmentaperture 153 on coupling end 152. Any number of bypass alignmentapertures located in any radial position on coupling end 152 is withinthe scope of this disclosure.

In various embodiments, main orifice plate 180 may further comprise afirst bypass aperture 902 disposed radially outward from aperture 910.In various embodiments, main orifice plate 180 may further comprise asecond bypass aperture 904 disposed approximately 180 degrees from thefirst bypass aperture 902. Any number of bypass apertures located in anyradial position on main orifice plate 180 is within the scope of thisdisclosure. In various embodiments, the number of bypass alignmentapertures on coupling end 152 corresponds to a number of bypassapertures on main orifice plate 180. In various embodiments, theorientation of the bypass alignment apertures on coupling end 152relative to each other may correspond to the orientation of the bypassapertures on main orifice plate 180.

Referring now to FIG. 9A only, a bypass closed configuration of a shockstrut assembly 100 from FIG. 1 is illustrated, in accordance withvarious embodiments. The bypass closed configuration may occur whenfirst bypass aperture 902 of main orifice plate 180 is misalignedcircumferentially with first bypass alignment aperture 153 of couplingend 152. Similarly, the second bypass aperture 904 of main orifice plate180 may be misaligned circumferentially with second bypass alignmentaperture 155 when in the bypass closed configuration.

A multi-actor damping system could open and close bypass apertures 902,904 depending on the actor angle. After rotating the main orifice plate180 as shown in FIG. 9A, the bypass apertures 902, 904 may be alignedwith bypass alignment apertures 153, 155 of coupling end 152 and openthe bypass apertures 902, 904, as shown in FIG. 9B. As such, FIG. 9Brepresents a bypass closed configuration of a shock strut assembly, inaccordance with various embodiments. Utilizing bypass apertures in thismanner may provide various damping actor configurations with or withoutthe use of flow restrictors. In various embodiments, bypass apertures902, 904 may shift an entire damping curve higher or lower depending onwhether they are in an open configuration or a closed configuration.

Controlling the bypass area may also be beneficial with regard topercolation, which occurs from a restriction of gas and oil flow acrossthe main orifice plate 180 when the hydraulic chamber is refilling aftera landing gear has been stored for flight and then extended for landing.

Referring now to FIGS. 10A-17B, the retraction of first flow restrictor162 and second flow restrictor 164 over various actor angles isillustrated, in accordance with various embodiments. Referring now toFIGS. 10A and 10B, cross-sections of a portion of a shock strut assemblyhaving a first orientation (i.e., a first damping actor configurationcorresponding to a first flow restrictor 162 and second flow restrictor164 being deployed) is illustrated, in accordance with variousembodiments. In the first damping actor configuration, the actor angleis approximately 0 degrees. In various embodiments, the actor angle isbetween −5 degrees and 5 degrees in the first damping actorconfiguration.

In various embodiments, the restrictor portion 620 of first flowrestrictor 162 and second flow restrictor 164 are each disposed in agroove (e.g., groove 822 of second flute profile 820 for first flowrestrictor 162 and groove 842 of second flute profile 820 for secondflow restrictor 164). The restrictor portion 620 may at least partiallycontact a respective groove (e.g., restrictor portion 620 of first flowrestrictor 162 may contact the groove 822 of second flute profile 820and restrictor portion 620 of second flow restrictor 164 may contact thegroove 842 of second flute profile 820). A restrictor angle may bedefined about a centerline of aperture 615. For example, a 0 degreeposition may be defined by a vector (e.g., vector A) extendingperpendicular from the centerline of aperture 615 of each flowrestrictor (e.g., aperture 615 of first flow restrictor 162 and aperture615 of second flow restrictor 164) to a tail end 629 of each flowrestrictor (e.g., tail end 629 of first flow restrictor 162 and tail end629 of second flow restrictor 164). In the first damping actorconfiguration, the flow restrictor angle for each flow restrictor may be0 degrees by definition (i.e., the first damping configuration sets afirst orientation about which the restrictor angle is measured from). Invarious embodiments, when the flow restrictor is fully deployed, therestrictor angle is 0 degrees by definition.

Referring now to FIGS. 11A and 11B, cross-sections of a portion of ashock strut assembly having a first orientation (i.e., an actor anglebetween a first damping actor configuration (e.g., fully deploy flowrestrictor) and a second damping actor configuration (e.g., a fullyretracted flow restrictor)) is illustrated, in accordance with variousembodiments. In the first orientation, the actor angle is approximately22.5 degrees. In various embodiments, the actor angle is between 20degrees and 25 degrees in the first orientation.

In various embodiments, the restrictor portion 620 of first flowrestrictor 162 and second flow restrictor 164 each remain partiallydisposed in a groove (e.g., groove 822 of second flute profile 820 forfirst flow restrictor 162 and groove 842 of second flute profile 820 forsecond flow restrictor 164). The restrictor portion 620 may at leastpartially contact a respective groove (e.g., restrictor portion 620 offirst flow restrictor 162 may contact the groove 822 of second fluteprofile 820 and restrictor portion 620 of second flow restrictor 164 maycontact the groove 842 of second flute profile 820). In the firstorientation, the restrictor angle for each flow restrictor may beapproximately 0 degrees. In various embodiments, the flow restrictorangle is between 0 degrees and 5 degrees in the first orientation.

With brief reference to FIGS. 6, 7 and 11A-B, in the first orientation,a protrusion of a flow restrictor may be proximate a first end of guideramp 710 (e.g., a protrusion 618 of first flow restrictor 162 may beproximate a first end of guide ramp 710 of a first orbit cam 167. Invarious embodiments, main orifice plate 180 may further comprise atongue 1102 disposed at a proximal end of the main orifice plate 180 andextending in the radial direction. The tongue 1102 may be received inthe groove 736 of second orbit cam 169. As metering pin 140 is furtherrotated about its center axis, the metering pin 140 applies a torque tomain orifice plate 180. The metering pin 140 may drive the rotation ofthe main orifice plate 180 while the second orbit cam 169 remainsstationary. The respective protrusion may be guided by guide ramp 710and begin to retract the respective flow restrictor (e.g., protrusion618 of first flow restrictor 162 may be guided by guide ramp 710 offirst orbit cam 167).

Referring now to FIGS. 12A and 12B, cross-sections of a portion of ashock strut assembly having a second orientation (i.e., an actor anglebetween the first orientation and a second damping actor configuration(e.g., a fully retracted flow restrictor)) is illustrated, in accordancewith various embodiments. In the second orientation, the actor angle isapproximately 45 degrees. In various embodiments, the actor angle isbetween 40 degrees and 50 degrees in the second orientation.

In various embodiments, the restrictor portion 620 of first flowrestrictor and second flow restrictor 164 may be partially removed fromthe original groove from first damping actor configuration and firstorientation (e.g., second flow restrictor 164 may be disposed outside ofgroove 842 for second flow restrictor 164 from FIG. 11B). In the secondorientation, the restrictor angle for each flow restrictor may beapproximately 14 degrees. In various embodiments, the restrictor anglemay be between 10 degrees and 19 degrees in second orientation.

With brief reference to FIGS. 6, 7 and 12A-B, in the second orientation,a protrusion of a flow restrictor may be disposed a first axial distancefrom a proximal end 732 of a respective orbit cam on guide ramp 710(e.g., a protrusion 618 of second flow restrictor 164 may be an axialdistance from the proximal end 732 of second orbit cam 169 on guide ramp710). As the protrusion 618 of second flow restrictor 164 travels on theguide ramp 710, the head portion 610 of second flow restrictor 164pivots about the aperture 615 of second flow restrictor 164 and altersthe flow restrictor angle as the second flow restrictor 164 begins toretract. As metering pin 140 is further rotated about its center axis,the respective protrusion may be guided by guide ramp 710 and begin toretract the respective flow restrictor (e.g., protrusion 618 of firstflow restrictor 162 may be guided by guide ramp 710 of first orbit cam167).

Referring now to FIGS. 13A and 13B, cross-sections of a portion of ashock strut assembly having a third orientation (i.e., an actor anglebetween the first and second orientation and a first and second dampingactor configuration (e.g., a fully retracted flow restrictor)) isillustrated, in accordance with various embodiments. In the thirdorientation, the actor angle is approximately 67.5 degrees. In variousembodiments, the actor angle is between 62.5 degrees and 72.5 degrees inthe third orientation.

In various embodiments, the restrictor portion 620 of first flowrestrictor and second flow restrictor 164 each remain proximate theirrespective grooves compared to first actor configuration, firstorientation, and second orientation (e.g., groove 842 of second fluteprofile 820 for second flow restrictor 164). The restrictor portion 620may be spaced apart from the respective groove (e.g., restrictor portion620 of second flow restrictor 164 may be spaced apart from groove 842 ofsecond flute profile 820). In the third orientation, the restrictorangle for each flow restrictor may be approximately 57 degrees. Invarious embodiments, the restrictor angle may be between 52 degrees and62 degrees in the third orientation.

With brief reference to FIGS. 6, 7 and 13A-B, in the third orientation,a protrusion of a flow restrictor may be disposed a second axialdistance from a proximal end 732 of a respective orbit cam on guide ramp710 (e.g., a protrusion 618 of second flow restrictor 164 may be anaxial distance from the proximal end 732 of second orbit cam 169 onguide ramp 710). The second axial distance may be greater than the firstaxial distance in the second orientation. As the protrusion 618 ofsecond flow restrictor 164 travels on the guide ramp 710, the headportion 610 of second flow restrictor 164 pivots about the aperture 615of second flow restrictor 164 and alters the flow restrictor angle asthe second flow restrictor 164 continues to retract. As metering pin 140is further rotated about its center axis, the protrusion 618 may beguided by guide ramp 710 and continue to retract the respective flowrestrictor (e.g., protrusion 618 of first flow restrictor 162 may beguided by guide ramp 710 of first orbit cam 167).

Referring now to FIGS. 14A and 43B, cross-sections of a portion of ashock strut assembly having a second actor damping configuration (i.e.,an orientation where with fully retracted flow restrictors) isillustrated, in accordance with various embodiments. In the second actordamping configuration, the actor angle is approximately 90 degrees. Invarious embodiments, the actor angle is between 80 degrees and 100degrees in the second actor damping configuration. In the second dampingactor configuration, the restrictor angle for each flow restrictor maybe approximately 81 degrees. In various embodiments, the restrictorangle may be between 76 degrees and 86 degrees in the third orientation.

With brief reference to FIGS. 6, 7 and 13A-B, in the second dampingactor configuration, a protrusion of a flow restrictor may be disposed athird axial distance from a proximal end 732 of a respective orbit camon guide ramp 710 (e.g., a protrusion 618 of second flow restrictor 164may be an axial distance from the proximal end 732 of second orbit cam169 on guide ramp 710). The third axial distance may be greater than thefirst axial distance in the second orientation and the second axialdistance in the third orientation. As the protrusion 618 of second flowrestrictor 164 travels on the guide ramp 710, the head portion 610 ofsecond flow restrictor 164 pivots about the aperture 615 of second flowrestrictor 164 and alters the flow restrictor angle as the second flowrestrictor 164 retracts entirely as it rotates from the thirdorientation to the second damping actor configuration. As metering pin140 is further rotated about its center axis, the protrusion 618 may beguided by guide ramp 710 and retract the respective flow restrictor(e.g., protrusion 618 of first flow restrictor 162 may be guided byguide ramp 710 of first orbit cam 167).

Referring now to FIG. 15, a cross-section of a portion of a shock strutassembly having with the metering pin and the main orifice plate hiddenis illustrated, in accordance with various embodiments. In variousembodiments, guide ramp 710 of orbit cam 700 extends axially away fromproximal end 732 as it travels circumferentially away from first matingsurface 702 and towards second mating surface 704 until it reaches amaximum axial distance D1 from proximal end 732 before it starts toextend axially towards proximal end 732 as it continues extendingcircumferentially until it reaches second mating surface 704.

Referring now to FIG. 16, an exploded view of a portion of a mainorifice assembly 160, in accordance with various embodiments, isillustrated. In various embodiments, the orbit cams may have radialfreedom along one line of motion while remaining clocked with the outersupport tube. This may be accomplished by including four flat matingsurfaces disposed approximately 90 degrees apart amongst multiplecomponents. For example, flat recess 724 of first orbit cam 167 mayinterface with a first flat recess 1624 disposed on a radially innersurface of main orifice plate retainer 184. Similarly, flat recess 724of second orbit cam 169 may interface with a second flat recess 1626disposed radially opposite the first flat recess 1624.

The main orifice plate retainer 184 may further comprise a first flatmating surface 1634 disposed on a radially outer surface of main orificeplate retainer 184 and a second flat mating surface disposed oppositethe first flat mating surface. Each flat mating surface of the mainorifice plate retainer 184 may mate with a corresponding flat matingsurface of the orifice support tube 150. For example, the second flatmating surface may mate with a second flat mating surface 1642 disposedon a radially inner surface of orifice support tube 150. Similarly,first flat mating surface 1634 may mate with a first flat mating surfacedisposed on a radially inner surface of orifice support tube 150, thefirst flat mating surface disposed radially opposite the second flatmating surface 1642.

The flat mating surface allow the metering pin, the main orifice plate180, first orbit cam 167, and second orbit cam 169 to translate togetherradially, while maintaining the first orbit cam 167 and the second orbitcam 169 aligned with the orifice support tube 150 in terms of actorangle. In various embodiments, the main orifice assembly 160 isconfigured to allow the first orbit cam 167 and the second orbit cam 169to be disposed radially inward of the orifice plate mount 182 and sliderelative to the main orifice plate mount in linear directions, whilepreventing rotation of the first orbit cam 167 and the second orbit cam169.

The main orifice assembly 160 may be configured to allow axial travel ofthe main orifice plate 180 during operation of a respective shock strutassembly. For example, main orifice plate mount 182 may mount the mainorifice plate retainer 184, first orbit cam 167, second orbit cam 169,and main orifice plate 180 within coupling end 152 of orifice supporttube 150 loosely in the axially direction. As such, main orifice plate180 may be configured to travel axially within the coupling end 152and/or rotate about a centerline of a respective metering pin.

Referring now to FIGS. 17A and 17B, a main orifice assembly 160 duringoperation of a shock strut assembly, in accordance with variousembodiments, is illustrated. FIG. 17A illustrates oil flow during strutcompression, and FIG. 17B illustrates oil flow during strut extension,in accordance with various embodiments. The coupling end 152 may furthercomprise a plurality of bypass flow apertures 1702.

With reference to FIGS. 1 and 17A, during strut compression, oil flowsfrom oil chamber 134 through main orifice assembly 160 and into orificesupport tube 150. During the strut compression, main orifice plate 180may be configured to travel axial in coupling end 152 of orifice supporttube 150 and contact an axial surface 1704 of coupling end 152. Bycontacting the axial surface 1704 of coupling end 152, the main orificeplate 180 may act as a seal between the oil flow between oil chamber 134and orifice support tube 150 and the plurality of bypass flow apertures1702.

With reference now to FIGS. 1 and 17B, during strut extension, oil flowsfrom orifice support tube 150 through the main orifice assembly 160 andinto oil chamber 134. The main orifice plate 180 may be configured toseparate axially from axial surface 1704 of coupling end 152. In thisregard, a bypass flow path may be created between the axial surface 1704and an axial surface 1706 of main orifice plate 180 through theplurality of bypass flow apertures 1702. The separation between theaxial surface 1704 of the coupling end 152 and the axial surface 1706 ofthe main orifice plate may be separated by a gap G1. The gap G1 may be adesign consideration and/or may be varied based on damping actor angleto meet a desired damping curve for a damping actor configuration. Forexample, G1 may vary for a given main orifice plate 180 as a function ofcircumferential position, or G1 may be fixed and varied based on initialdesign considerations. In a design where G1 varies as a function ofcircumferential position, a gap G1 can correspond with a damping actorconfiguration to either provide higher damping or lower damping. Forexample, a larger G1 may corresponded to a lesser damping curve, whereasa smaller G1 may correspond to a greater damping curve.

Referring now to FIG. 18, a main orifice assembly 160, in accordancewith various embodiments, is illustrated. Main orifice assembly 160 mayfurther comprise first spring 192 coupled to first flow restrictor 162and second spring 194 coupled to second flow restrictor 164. Each spring192, 194 may be any spring known in the art, such as a mooring ringspring, or the like. Each flow restrictor may further comprise a springpocket defined at least partially by first recess 626 and second recess619, as defined in FIG. 6. For example, first flow restrictor 162 maycomprise a spring pocket 1802 configured to house the first spring 192.

In various embodiments, each spring deflection curve may be relativelyflat (i.e., the curve may plateau at a threshold displacement). A springforce of each spring may be minimized resulting in reduced torque tochange damping actor configurations and reducing restriction of the flowrestrictors for oil refilling the hydraulic chamber when the strut isextending.

Referring now to FIG. 19, a main orifice plate assembly 1980 and ametering pin 140, in accordance with various embodiments, isillustrated. In various embodiments, orifice plate assembly 1980 maycomprise a metering plate 180, a first flow restrictor 162 coupled tothe main orifice plate 180 and as second flow restrictor 164 coupled tothe main orifice plate 180. In various embodiments, a first lug and asecond lug in the plurality of lugs may be coupled to a respective flowrestrictor. For example, first lug 1902 and second lug 1904 may define aflange fork. A head portion 610 of first flow restrictor 162 may bedisposed in the flange fork. With combined reference to FIGS. 6 and 19,a pin may be disposed through a first aperture 1912 of first lug 1902through aperture 615 of head portion 610 and through a correspondingsecond aperture of second lug 1904. The pin may act as a fulcrum for thefirst flow restrictor to rotate about.

In various embodiments, each lug in the plurality of lugs may extendaxially beyond the head portion 610 of a respective flow restrictor. Inthis regard, each lug in the plurality of lugs 186 may restrict flowaround the respective flow restrictor when positioned for maximum flutedepth. A consistent level of leakage may be set based on a distancebetween each lug in the plurality of lugs 186 and the metering pin 140.

Referring now to FIG. 20, a portion of a shock strut assembly 2000including a main orifice assembly 2060 from a bottom view, in accordancewith various embodiments, is illustrated. “Bottom view,” as referred toherein is a view looking from damping actor selector 170 towards orificesupport tube 150 in FIG. 1. In various embodiments, shock strut assembly2000 is for a steerable gear.

Referring back to FIG. 1, a “steering angle,” as defined herein, is arelative clock angle between the strut cylinder 110 and the strut piston120. A “damping actor selector (DAS) angle” as defined herein is arelative clock angle between the metering pin 140 and the strut piston120. In various embodiments, the damping actor selector 170 rotates themetering pin 140 relative to the strut piston 120 and steering rotatesthe strut piston 120 relative to the strut cylinder 110. As such, theactor angle may be the sum of both the steering angle and the DAS angle.

As a steerable gear, the steering angle of shock strut assembly 2000 maybe approximately 360 degrees. However, steering during a first dampingactor configuration 2002 may be limited to a first steering range and/orsteering during a second damping actor configuration 2004 may be limitedto a second steering range. The steering ranges of each damping actorconfiguration may be a design choice.

Referring back to FIG. 20, an actor angle 2010 may be defined between afirst damping actor configuration 2002 and a second damping actorconfiguration 2004 based on a steering range of each damping actorconfiguration. For example, with reference to FIGS. 7 and 20, if a firstdamping actor configuration 2002 has 74 degrees of steering (−37 degreesto 37 degrees from a neutral position), and the second damping actorconfiguration 2004 has 24 degrees of steering (−37 degrees to 37 degreesfrom a neutral position), and the neutral positions of the first dampingactor configuration 2002 and the second damping actor configuration 2004are 90 degrees apart (i.e., a 90 degree actor angle), a guide ramp 710of an orbit cam 700 may span 41 degrees maximum (e.g., 90 degrees-12degrees-37 degrees). Additionally, in this configuration, the start ofthe guide ramp may be at least 37 degrees from a first mating surface702 and the maximum axial distance D1 may occur at a maximum of 88degrees. Furthermore, the maximum axial distance D1 of the guide rampmay span at least 24 degrees, corresponding, at a minimum, to thesteering angle while in the second damping actor configuration.

Referring to FIGS. 1 and 20, to change damping actor configuration(i.e., from first damping actor configuration 2002 to second dampingactor configuration 2004), the damping actor selector 170 may rotate themetering pin clockwise or counterclockwise by the actor angle (e.g., 90degrees in FIG. 20). In various embodiments, first damping actorconfiguration 2002 may correspond to a first flow restrictor 162 andsecond flow restrictor 164 being fully retracted. In variousembodiments, second damping actor configuration 2004 may correspond tothe first flow restrictor 162 and the second flow restrictor 164 beingfully deployed. In various embodiments, first damping actorconfiguration may correspond to a damping curve configured for landingof an aircraft. In various embodiments, the second damping actorconfiguration may correspond to catapult of an aircraft.

Referring now to FIG. 21, a portion of a shock strut assembly 2100including a main orifice assembly 2160 from a bottom view, in accordancewith various embodiments, is illustrated. In various embodiments, shockstrut assembly 2100 is for a non-steerable gear. In various embodiments,a non-steerable gear may be configured to have multiple damping actorconfigurations. For example, a shock strut assembly 2100 for anon-steerable gear may comprise a first damping actor configuration2102, a second damping actor configuration 2104, a third damping actorconfiguration 2106, and/or a fourth damping actor configuration 2108.

In various embodiments, the first damping actor configuration 2102 maycorrespond to a damping curve designed for a percolation event.Percolation occurs when restriction of gas and oil flow across the mainorifice assembly 2160 when the hydraulic chamber is refilling after alanding gear has been stowed for flight. In the first damping actorconfiguration 2102, the main orifice assembly 2160 may open a large flowarea between the hydraulic and gas chambers in order to facilitate agas/oil migration between the chambers. This may allow an aircraft tosafely land within a shorter time interval after lowering a gear.

In various embodiments, the second damping actor configuration 2104 maycorrespond to a damping curve designed for conventional takeoff and land(CTOL). In various embodiments, the third damping actor configuration2106 may correspond to a damping curve designed for short takeoff andvertical landing (STOVL). The third damping actor configuration 2106 maybe tuned for vertical landings. For example, the third dampingconfiguration may provide greater energy absorption since spin-up andspring back effects may have less influence. The third damping actorconfiguration may also correspond to a damping curve designed for roughterrain.

In various embodiments, the fourth damping actor configuration 2108 maycorrespond to a damping curve designed for taxi of an aircraft. Thefourth damping actor configuration may be optimized for ride quality, orthe like.

In various embodiments and with additional reference to FIG. 22, aschematic block diagram of a control system 2200 for damping actorselector 2270 is illustrated. Control system 2200 includes a controller2202 in electronic communication with a launch bar lock 2204 and asensor 2206. In various embodiments, controller 2202 may be integratedinto computer systems onboard aircraft. In various embodiments,controller 2202 may be configured as a central network element or hub toaccess various systems, engines, and components of control system 2200.Controller 2202 may comprise a network, computer-based system, and/orsoftware components configured to provide an access point to varioussystems, engines, and components of control system 2200. In variousembodiments, controller 2202 may comprise a processor. In variousembodiments, controller 2202 may be implemented in a single processor.In various embodiments, controller 2202 may be implemented as and mayinclude one or more processors and/or one or more tangible,non-transitory memories and be capable of implementing logic. Eachprocessor can be a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof. Controller 2202 may comprise a processor configuredto implement various logical operations in response to execution ofinstructions, for example, instructions stored on a non-transitory,tangible, computer-readable medium configured to communicate withcontroller 2202.

System program instructions and/or controller instructions may be loadedonto a non-transitory, tangible computer-readable medium havinginstructions stored thereon that, in response to execution by acontroller, cause the controller to perform various operations. The term“non-transitory” is to be understood to remove only propagatingtransitory signals per se from the claim scope and does not relinquishrights to all standard computer-readable media that are not onlypropagating transitory signals per se. Stated another way, the meaningof the term “non-transitory computer-readable medium” and“non-transitory computer-readable storage medium” should be construed toexclude only those types of transitory computer-readable media whichwere found in In Re NuUten to fall outside the scope of patentablesubject matter under 35 U.S.C. § 101.

In various embodiments, controller 2202 may be in electroniccommunication with launch bar lock 2204 and/or sensor 2206. When launchbar lock 2204 is on, a switch may be closed and the launch bar lock 2204may be engaged/locked. When launch bar lock 2204 is off, a switch may beclosed, and the aircraft may be configured for a catapult launch. Sensor2206 may comprise any load cell known in the art, such as a compressionload cell, or the like. Sensor 2206 may be configured to measure aweight of on wheels and indicate whether the aircraft is on ground.Sensor 2206 and launch bar lock 2204 may be configured to transmitsignals to controller 602, thereby providing a phase of flight tocontroller 2202.

In various embodiments, controller 2202 may receive a catapult commandto extend a launch bar lock 2204 to a deck in order to configure theaircraft for a catapult launch. In response to the catapult command, thecontroller 2602 may command the damping actor selector 2270 totransition from a first damping actor configuration to a second dampingactor configuration. In response, the damping actor selector 2270 mayrotate the metering pin 140 and the main orifice plate 180 in a firstdirection about a central axis of the metering pin 140 and/or deploy afirst flow restrictor 162 and/or a second flow restrictor 164. Invarious embodiments, when the sensor 2206 no longer measures a weight onwheels of the aircraft, the controller 2202 may command the dampingactor selector 2270 to transition back from the second damping actorconfiguration to the first damping actor configuration. In this regard,the damping actor selector 2270 may rotate the metering pin 140 and themain orifice plate 180 in a second direction about the central axis ofthe metering pin 140 and/or retract the first flow restrictor 162 and orthe second flow restrictor 164. The second direction may be opposite ofthe first direction.

In various embodiments, the launch bar lock 2204 may re-engage aftercatapult launch. In response, if the sensor still measures a weight onwheels when the launch bar lock 2204 re-engages a lock, the controller2202 may command the damping actor selector 2270 to transition back fromthe second damping actor configuration to the first damping actorconfiguration. In this regard, the damping actor selector 2270 mayrotate the metering pin 140 and the main orifice plate 180 in a seconddirection about the central axis of the metering pin 140 and/or retractthe first flow restrictor 162 and or the second flow restrictor 164. Thesecond direction may be opposite of the first direction.

In various embodiments, the controller 2202 may command the launch barlock 2204 to re-engage after catapult launch. In response, if the sensorstill measures a weight on wheels, the controller 2202 may command thedamping actor selector 2270 to transition back from the second dampingactor configuration to the first damping actor configuration. In thisregard, the damping actor selector 2270 may rotate the metering pin 140and the main orifice plate 180 in a second direction about the centralaxis of the metering pin 140 and/or retract the first flow restrictor162 and or the second flow restrictor 164. The second direction may beopposite of the first direction.

Referring now to FIG. 23, a method 2300 of setting an actor angle of amulti-actor damping system is illustrated, in accordance with variousembodiments. The method comprises rotating, via a damping actorselector, a metering pin about a central axis of the metering pin in afirst direction from a default position (step 2302). The defaultposition may correspond to a first damping actor configuration. Thefirst damping actor configuration may comprise a damping curveconfigured for convention landing or the like. The damping actorselector may be in accordance with damping actor selector 170. Themethod may further comprise setting, via the damping actor selector, afirst actor angle of the multi-actor damping system (step 2304). Thefirst actor angle may correspond to a second damping actorconfiguration. The second damping actor configuration may comprise adamping curve configured for catapult launch, or the like.

The method may further comprise rotating, via the damping actorselector, the metering pin about the central axis of the metering pin ina second direction (step 2306). In various embodiments, the seconddirection may be the same as the first direction in a multi-actordamping system where with more than two damping actor configurations(e.g., for a non-steerable landing gear). In various embodiments, thesecond direction may be opposite the first direction in a multi-actordamping system where there are only two damping actor configurations(e.g., for a steerable landing gear). The method may further comprisesetting a second actor angle (step 2308). The second actor angle may bedifferent than the first actor angle. The second actor angle maycorrespond to the first damping actor configuration or a third dampingactor configuration. The second actor angle may be the negative firstactor angle in a steerable landing gear system. The third damping actorconfiguration may comprise a damping curve configured for short takeoffand vertical landing, taxi, or the like.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure.

The scope of the disclosure is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” It is to be understood that unlessspecifically stated otherwise, references to “a,” “an,” and/or “the” mayinclude one or more than one and that reference to an item in thesingular may also include the item in the plural. All ranges and ratiolimits disclosed herein may be combined.

Moreover, where a phrase similar to “at least one of A, B, and C” isused in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C.

The steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Elements and steps in the figuresare illustrated for simplicity and clarity and have not necessarily beenrendered according to any particular sequence. For example, steps thatmay be performed concurrently or in different order are illustrated inthe figures to help to improve understanding of embodiments of thepresent disclosure.

Any reference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.Surface shading lines may be used throughout the figures to denotedifferent parts or areas but not necessarily to denote the same ordifferent materials. In some cases, reference coordinates may bespecific to each figure.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment,” “an embodiment,”“various embodiments,” etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A method for changing a damping curve of a shockstrut assembly, the method comprising: rotating, via a damping actorselector, a main orifice plate from a default position about acenterline of a metering pin in a first direction, the default positioncorresponding to a first damping actor configuration; setting, via thedamping actor selector, a first actor angle corresponding to a seconddamping actor configuration.
 2. The method of claim 1, wherein the firstdamping actor configuration includes a first damping curve, wherein thesecond damping actor configuration includes a second damping curve, andwherein the first damping curve and the second damping curve aredifferent.
 3. The method of claim 2, wherein the first damping curve isfor conventional landing of an aircraft.
 4. The method of claim 3,wherein the second damping curve is for a catapult launch of theaircraft.
 5. The method of claim 1, further comprising rotating, via thedamping actor selector, the metering pin from the first actor angle to asecond actor angle.
 6. The method of claim 5, wherein the second actorangle corresponds to the first damping actor configuration.
 7. Themethod of claim 5, wherein the second actor angle corresponds to a thirddamping configuration.
 8. The method of claim 7, wherein the firstdamping actor configuration includes a first damping curve, wherein thesecond damping actor configuration includes a second damping curve,wherein the third damping configuration includes a third damping curve,wherein the first damping curve is different from the second dampingcurve, wherein the second damping curve is different than the firstdamping curve, and wherein the first damping curve is different from thethird damping curve.
 9. The method of claim 1, wherein the first actorangle is a relative clock angle between the metering pin and a strutcylinder.
 10. A method of selecting a damping configuration of a shockstrut assembly for an aircraft, the method comprising: sending, by acontroller, a catapult launch command to a launch bar lock and a dampingactor selector; extending, by the controller, the launch bar lock to adeck of the aircraft to configure the aircraft for a catapult launch;and transitioning, via the controller, the damping actor selector from afirst damping actor configuration to a second damping actorconfiguration in response to the catapult launch command.
 11. The methodof claim 10, wherein the first damping actor configuration correspondsto a first damping curve, wherein the second damping actor configurationcorresponds to a second damping actor curve, and wherein the firstdamping curve and the second damping actor curve are different.
 12. Themethod of claim 10, wherein transitioning the damping actor selectorfrom the first damping actor configuration to the second damping actorconfiguration further comprises setting an actor angle, wherein theactor angle is a relative clock angle between a metering pin and a strutcylinder.
 13. The method of claim 10, further comprising transitioning,via the controller, the damping actor selector from the second dampingactor configuration to the first damping actor configuration in responseto receiving a signal from a sensor that a wheel is not experiencing aload.
 14. The method of claim 10, further comprising sending, by thecontroller, a re-engage command to the launch bar lock and the dampingactor selector; and transitioning, via the controller, the damping actorselector from the second damping actor configuration to the firstdamping actor configuration in response to the re-engage command.
 15. Ashock strut assembly, comprising: a strut cylinder including a primarychamber; a strut piston, the strut cylinder configured to receive thestrut piston; an orifice support tube positioned within the primarychamber of the strut cylinder; a main orifice assembly disposed withinthe orifice support tube, the main orifice assembly including a mainorifice plate; a metering pin positioned within the primary chamber, themetering pin defining an axis; and a damping actor selector operablycoupled to the main orifice plate, the damping actor selector configuredto rotate the main orifice plate and transition the shock strut assemblyfrom a first damping actor configuration to a second damping actorconfiguration.
 16. The shock strut assembly of claim 15, wherein thedamping actor selector comprises hydraulic actuation or pneumaticactuation.
 17. The shock strut assembly of claim 15, wherein the dampingactor selector comprises at least one of an electric stepper or a servomotor.
 18. The shock strut assembly of claim 15, wherein the dampingactor selector comprises a piston head coupled to the metering pin. 19.The shock strut assembly of claim 18, wherein the metering pin rotatesin response to the piston head traveling linearly along the axis. 20.The shock strut assembly of claim 15, wherein the first damping actorconfiguration includes a first damping curve, wherein the second dampingactor configuration includes a second damping curve, and wherein thefirst damping curve is different than the second damping curve.